Data Relay for a Controller

ABSTRACT

An irrigation system includes an irrigation controller, at least one environmental sensor and a vandal resistant data relay. The irrigation controller includes a two conductor hard wired communications link for accepting an actual value of at least one parameter of interest from an environmental sensor in the form of data encoded on the conductors via current modulation. The environmental sensor is mounted in a location remote from the irrigation controller. A circuit is connected to the environmental sensor for transmitting an RF signal representing an actual value of a parameter of interest detected by the environmental sensor. The vandal resistant data relay is connected to the two conductor hard wired communication link of the irrigation controller. The vandal resistant data relay includes a receiver that receives the RF signal, and circuitry configured to extract the actual value of the parameter of interest and emulate a predetermined set of physical and protocol properties of the two conductor hard wired communication link of the irrigation controller.

FIELD OF THE INVENTION

The present invention relates to data communication, and moreparticularly, to wireless data communication devices.

BACKGROUND

An irrigation controller sometimes uses signals from remoteenvironmental sensors that detect rain events, temperature, solarradiation, wind speed, humidity, soil moisture, evapotranspiration,flow, or other parameters. Typically the irrigation controller and thesensor communicate through a hard wired connection. Many times the hardwired connection uses the same pair of wires to supply power to thesensor, as it does to communicate information back to the irrigationcontroller. Other times separate wires are used for power and control.One of the reasons the communications link is typically a hard wiredconnection is the fact that many times the irrigation controller isinstalled in a vandal-resistant metal cabinet that shields RF signals,making it impractical to use a wireless communications link. Anotherreason that the communications link is typically a hard wired connectionis that an RF receiver circuit typically costs significantly more than asimple hard wire receiver circuit.

As previously mentioned, irrigation controllers conventionally retrievedata from a remote sensor using a two conductor hard wired connection.Typically a pair of wires carry both an excitation voltage to power thesensor as well as data in the form of a modulated current draw. Datacontaining environmental information of interest is communicated to theirrigation controller by modulating the amount of current drawn by theenvironmental sensor that is sending the data. Current modulation istypically more noise tolerance and affected less by long wire runs, thana voltage modulated signal.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention a data relayincludes an RF receiver, a demodulator, a microcontroller and a currentmodulator. The RF receiver is configured to receive an RF signaltransmitted from a remote location representing data from a sensor. Thedemodulator retrieves a base band data signal from the received RFsignal. The microcontroller receives the base band data signal anddetermines an actual value of at least one parameter of interest. Thecurrent modulator is controlled by the microcontroller and transmits theactual value of the parameter of interest to a controller on a pair ofconductors by emulating a predetermined set of physical and protocolproperties of a predetermined two conductor hard wired communicationlink of the controller.

In accordance with another aspect of the present invention an irrigationsystem includes an irrigation controller, at least one environmentalsensor and a vandal resistant data relay. The irrigation controllerincludes a two conductor hard wired communications link for accepting anactual value of at least one parameter of interest from an environmentalsensor in the form of data encoded on the conductors via currentmodulation. The environmental sensor is mounted in a location remotefrom the irrigation controller. A circuit is connected to theenvironmental sensor for transmitting an RF signal representing anactual value of a parameter of interest detected by the environmentalsensor. The vandal resistant data relay is connected to the twoconductor hard wired communication link of the irrigation controller.The vandal resistant data relay includes a receiver that receives the RFsignal, and circuitry configured to extract the actual value of theparameter of interest and emulate a predetermined set of physical andprotocol properties of the two conductor hard wired communication linkof the irrigation controller.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an irrigation system incorporating anembodiment of the data relay of the present invention.

FIG. 2 is a schematic diagram of the circuitry of the data relay thatforms part of the system FIG. 1.

FIGS. 3A, 3B and 3C are front isometric, rear isometric and verticalsectional views, respectively, of a data relay module in accordance withthe present invention.

FIG. 4 is an isometric view of the data relay module of FIGS. 3A, 3B and3C attached to a junction box connected to electrical conduit.

FIG. 5 is an isometric view of the data relay module of FIGS. 3A, 3B and3C mounted on a metallic box that houses an irrigation controller.

DETAILED DESCRIPTION

The entire disclosures of the following U.S. patents and U.S. patentapplications are hereby incorporated by reference: U.S. Pat. No.5,097,861 granted Mar. 24, 1992 of Hopkins et al. entitled IRRIGATIONMETHOD AND CONTROL SYSTEM; U.S. Pat. No. 5,444,611 granted Aug. 22, 1995of Peter J. Woytowitz, et al. entitled LAWN AND GARDEN IRRIGATIONCONTROLLER; U.S. Pat. No. 5,829,678 granted Nov. 3, 1998 of Richard E.Hunter et al. entitled SELF-CLEANING IRRIGATION REGULATOR VALVEAPPARATUS; U.S. Pat. No. 6,088,621 granted Jul. 11, 2000 also of PeterJ. Woytowitz et al. entitled PORTABLE APPARATUS FOR RAPID REPROGRAMMINGOF IRRIGATION CONTROLLERS; U.S. Pat. No. 6,721,630 granted Apr. 13, 2004also of Peter J. Woytowitz entitled EXPANDABLE IRRIGATION CONTROLLERWITH OPTIONAL HIGH-DENSITY STATION MODULE; U.S. Pat. No. 6,842,667granted Jan. 11, 2005 of Beutler et al. entitled POSITIVE STATION MODULELOCKING MECHANISM FOR EXPANDABLE IRRIGATION CONTROLLER; U.S. patentapplication Ser. No. 10/883,283 filed Jun. 30, 2004 also of Peter J.Woytowitz entitled HYBRID MODULAR/DECODER IRRIGATION CONTROLLER, nowU.S. Pat. No. 7,069,115 granted Jun. 27, 2007; pending U.S. patentapplication Ser. No. 10/985,425 filed Nov. 9, 2004 also of Peter J.Woytowitz et al. and entitled EVAPOTRANSPIRATION UNIT CONNECTABLE TOIRRIGATION CONTROLLER; pending U.S. patent application Ser. No.11/288,831 filed Nov. 29, 2005 of LaMonte D. Porter et al. and entitledEVAPOTRANSPIRATION UNIT FOR RE-PROGRAMMING AN IRRIGATION CONTROLLER;U.S. patent application Ser. No. 11/045,527 filed Jan. 28, 2005 also ofPeter J. Woytowitz entitled DISTRIBUTED ARCHITECTURE IRRIGATIONCONTROLLER, now U.S. Pat. No. 7,245,991 granted Jul. 17, 2007; U.S. Pat.No. 7,289,886 of Peter J. Woytowitz granted Oct. 30, 2007 entitledMODULAR IRRIGATION CONTROLLER WITH SEPARATE FIELD VALVE LINE WIRINGTERMINALS; U.S. Pat. No. 7,225,058 of Lamonte D. Porter granted May 29,2007 entitled MODULAR IRRIGATION CONTROLLER WITH INDIRECTLY POWEREDSTATION MODULES; U.S. patent application Ser. No. 11/458,551 filed Jul.19, 2006 of Lamonte D. Porter et al. entitled IRRIGATION CONTROLLER WITHINTERCHANGEABLE CONTROL PANEL; and pending U.S. patent application Ser.No. 12/042,301 filed Mar. 4, 2008 of Peter J. Woytowitz et al. entitledIRRIGATION CONTROLLER WITH SELECTABLE WATERING RESTRICTIONS. Theaforementioned U.S. patents and applications are all assigned to HunterIndustries, Inc., the assignee of the subject application.

The present invention provides a vandal resistant data relay whichadapts a hard wired data interface into a wireless infrastructure. Whilethe embodiment described herein functions with an irrigation controlleras part of an evapotranspiration (ET) based irrigation system, the datarelay could be used in other applications such as lighting controllersand industrial automation. The described embodiment functions with anirrigation controller that receives data encoded by modulating currenton a two wire hard wired connection. However, the present invention canbe adapted for use with other physical layers (wiring configurations andsignal characteristics). In each of these applications, signals arebrought into a controlling device, such as an irrigation controller,where these signals represent some useful piece of information which thecontrolling device uses to optimally achieve its function. In the caseof an ET based irrigation controller, the information can represent,rain events, temperature, solar radiation, wind speed, humidity, soilmoisture, evapotranspiration, flow, or other parameters. In the case ofa lighting controller, the information could represent ambient light,temperature, detected motion or other parameters.

The data relay of the present invention adapts a control system designedfor hard wired data gathering into a wireless system, while maintainingvandal resistance. This allows the control system to be manufactured inits reduced cost version, without burdening every unit produced with theadditional cost associated with the wireless communications capability.The data relay of the present invention contains an RF receiver ortransceiver, that gathers data from a wireless sensor (or other dataretrieval device) that contains a transmitter (or transceiver), and thenemulates the physical and protocol layers of the analogous hardwiredsensor, to the controller. This data relay functionality is transparentto the controller, i.e. the controller does not “know” that the actualsensor is wirelessly connected. This feature is advantageous in keepingthe design of the controller free from hardware, protocol, and softwarevariations.

FIG. 1 is a block diagram of an irrigation system 10 incorporating anembodiment 12 of the data relay of the present invention. An irrigationcontroller 14 turns a plurality of irrigation valves 160N and OFF inaccordance with a watering program. The data relay 12 is connected by ahard wired connection 18 to an ET module 20 which is in turn connectedby a hard wired connection 22 to the irrigation controller 14. The datarelay 12 receives RF signals from a weather station 24 via antenna 26.The weather station 24 includes a plurality of environmental sensors 28such as a temperature sensor and a solar radiation sensor. The weatherstation 28 includes processing circuitry for encoding the signals fromthe sensors and sending them wirelessly to the data relay 12 viatransmitter 30 and antenna 32. Thus the irrigation system 10 has awireless communications link represented diagrammatically by parallel EMpropagation waves 34.

The irrigation controller 14 may be the Pro-C® manufactured by HunterIndustries, Inc. The ET module 20 and the weather station 28 may be theSolar Sync® units manufactured by Hunter Industries, Inc. See pendingU.S. patent application Ser. No. 12/181,894 filed Jul. 29, 2008 of PeterJ. Woytowitz et al. entitled IRRIGATION SYSTEM WITH ET BASED SEASONALWATERING ADJUSTMENT, the entire disclosure of which is herebyincorporated by reference.

FIG. 2 is a schematic diagram of the circuitry of the data relay 12.Incoming RF is first coupled to the receiving antenna 26, and thenrouted to a surface acoustic wave (SAW) filter, F1, which rejects anystrong out-of-band signals that would otherwise “blind” an RF receiver.The SAW filter may be a type B3760 manufactured by Epcos. Thisparticular model is designed to pass signals in the 434 MHZ band. Afterthe filter, the RF signal is presented to RF receiver IC, U3, afterpassing through matching components which assure the maximum possibleenergy is transferred to the IC. The receiver itself may be a typeMAX1473 available from Maxim Integrated Products. This receiver IC ishighly integrated and provides low noise amplifier (LNA), phased lockedloop (PLL), local oscillator (LO), and mixer circuitry internal to thepart. Specifically, a reference crystal, Y1, of 6.6128 MHZ is fed into aphase locked loop in order to create a local oscillator frequency of423.22 MHZ. This LO signal is mixed with an amplified version of theincoming RF signal to generate the intermediate frequency (IF) signal.This signal is amplified and brought out of the chip for filtering. Thedesigner has their choice of IF filtering options. This design uses a230 KHZ filter centered around 10.7 MHZ in order to filter the IFsignal. This filter is a type SFTLA10M7FA00-B0 available from Murata.The filtered IF signal is then fed back into the receiver where thedemodulation process retrieves the baseband data signal that wastransmitted by the sensor and presents it to microcontroller U2. Thismay be a type PIC12F629 available from Microchip Technology. Themicrocontroller parses the RF data, determines the actual value of theparameter of interest, and then drives the current modulation circuitrywhich is comprised of bipolar Transistor Q1 and resistor R8, in afashion that emulates the physical and protocol properties of the hardwired link. U1 is a simple linear voltage regulator such as a LM78L05,which takes the unregulated excitation voltage on the two wire path andgenerates a regulated 5VDC signal to power the microcontroller and RFcircuitry. Diodes D1-D4 form an incoming bridge rectifier whicheliminates any polarity sensitivity of the incoming two conductorsignal.

An advantageous aspect of the illustrated embodiment 12 of the datarelay of present invention pertains to its physical configuration in theform of a compact data relay module 36 (FIGS. 3A, 3B and 3C). Because ofthe level of integration available in modern IC's, the RF circuitry,microcontroller to supervise it, and power supply can all fit on aprinted circuit board (PCB) 38 (FIG. 3C) measuring only one to twosquare inches in area. The PCB 38 is housed inside a compact rectangularouter housing 40 that supports the short antenna 26. The antenna 26 isembedded inside an outer protective jacket 42. The outer housing 40includes a hollow cylindrical stub 44 (FIG. 3B) with a standard malepipe thread that allows it to be screwed into any standard pipe fittingwith a female thread such as provided on an electrical junction box 46connected to electrical conduit 48 leading to an electrical junction box50 containing the irrigation controller 14. The cylindrical stub 44 mayalso be inserted through a standard knock-out through the side wall ofthe electrical junction box 50 as illustrated in FIG. 5. The electricaljunction box 48 may be made of sheet metal, such as stainless steelsheet metal or it may be made of plastic. Wires (not illustrated) passfrom the data relay circuitry of FIG. 2 to the irrigation controller 14through the bore 48 of the stub 44.

The data relay module 36 emulates the physical and protocol layers ofthe hard wired communications link otherwise used to connect to thesensors 28. The physical configuration of the data relay module 36 has anumber of practical advantages. For example, it provides the capabilityof mounting the data relay module 36 outside of a metal box, therebyproviding a wireless solution into a metal enclosure, which wouldotherwise shield and prevent the entry any RF signal containinginformation from environmental sensors. This solution is different thansimply providing relay circuitry inside the metal enclosure andconnecting the same to an antenna mounted outside of the metal enclosurewhich may not be vandal resistant. The antenna would have to beconnected to the RF receiver using special coaxial RF cabling which isboth costly and difficult to splice. Furthermore, the more cable that isadded, the greater the RF loss and lower the range for the system. Thedata relay module 36 provides an integrated and optimal RF solutionwhich places the antenna 26 as close as possible to the receiver, whileallowing the remote function to be accomplished with also any kind ofcable.

The irrigation controller 14 may not be in an area conducive to wirelessreception. For instance, the irrigation controller 14 may be mounted onwall inside a garage which has metallic siding on the outside thatshields the RF signals. The irrigation controller 14 may be mounted in abasement which is subterranean and receives very little RF energy. Inthese situations, the data relay module 36 may be mounted in a locationthat allows for better reception such as on the outside wall of thegarage, and hard wired to the irrigation controller 14.

While I have described an embodiment of a data relay that isparticularly suited for use in an irrigation system, it will be apparentto those skilled in the art that my invention can be used in otherapplications. In addition, modifications and adaptations of my datarelay will occur to such skilled persons. Therefore, the protectionafforded my invention should only be limited in accordance with thescope of the following claims.

1. A data relay, comprising: an RF receiver configured to receive an RFsignal transmitted from a remote location representing data from asensor; a demodulator that retrieves a base band data signal from thereceived RF signal; a microcontroller that receives the base band datasignal and determines an actual value of at least one parameter ofinterest; and a current modulator controlled by the microcontroller thattransmits the actual value on a pair of conductors by emulating apredetermined set of physical and protocol properties of a predeterminedtwo conductor hard wired communication link of a controller.
 2. The datarelay of claim 1 and further comprising a housing enclosing thereceiver, demodulator, microcontroller and current modulator, andantenna connected to the receiver.
 3. The data relay of claim 2 whereinthe housing includes a threaded hollow cylindrical stub for screwinginto a knock out in a metal box housing the controller or into anelectrical conduit, the stub having a hollow bore for routing a pair ofwires that form a part of the two conductor hard wired communicationlink of the controller.
 4. The data relay of claim 1 wherein thereceiver includes a low noise amplifier (LNA), phase locked loop (PPL),local oscillator (LO), and mixer circuitry.
 5. The data relay of claim 2wherein the antenna extends from the housing and a protective jacketsurrounds the antenna.
 6. An irrigation system, comprising: anirrigation controller including a two conductor hard wiredcommunications link for accepting an actual value of at least oneparameter of interest from an environmental sensor in the form of dataencoded on the conductors via current modulation; at least oneenvironmental sensor mounted in a location remote from the irrigationcontroller; a circuit connected to the environmental sensor fortransmitting an RF signal representing an actual value of a parameter ofinterest detected by the environmental sensor; and a vandal resistantdata relay connected to the two conductor hard wired communication linkof the irrigation controller and including a receiver that receives theRF signal, and circuitry configured to extract the actual value of theparameter of interest and emulate a predetermined set of physical andprotocol properties of the two conductor hard wired communication linkof the irrigation controller.
 7. The irrigation system of claim 6 andfurther comprising a housing enclosing the data relay and an antennaconnected to the receiver.
 8. The irrigation system of claim 7 whereinthe housing includes a threaded hollow cylindrical stub for screwinginto a knock out in the metal box housing the irrigation controller. 9.The irrigation system of claim 6 wherein the receiver includes a lownoise amplifier (LNA), phase locked loop (PPL), local oscillator (LO),and mixer circuitry.
 10. The data irrigation system of claim 7 whereinthe antenna extends from the housing and a protective jacket surroundsthe antenna.
 11. A vandal resistant data relay, comprising: a receiverthat receives an RF signal encoded with at least one environmentalparameter of interest; circuitry that extracts an actual value of theparameter of interest from the RF signal and emulates a predeterminedset of physical and protocol properties of a two conductor hard wiredcommunication link of an irrigation controller; a housing that enclosesthe receiver and the extraction and emulation circuitry and includes athreaded hollow cylindrical stub for screwing into a knock out in ametal box housing the irrigation controller or into an electricalconduit, the stub having a hollow bore for routing a pair of wires thatform a part of the two conductor hard wired communication link of thecontroller; and an antenna connected to the receiver.
 12. The vandalresistant data relay of claim 11 wherein in the receiver includes a lownoise amplifier (LNA), phase locked loop (PPL), local oscillator (LO),and mixer circuitry.
 13. The vandal resistant data relay of claim 11wherein the extraction and emulation circuitry includes a demodulatorthat retrieves a base band data signal from the received RF signals. 14.The vandal resistant data relay of claim 13 wherein the extraction andemulation circuitry further includes a microcontroller that receives thebase band data signal and determines an actual value of at least oneparameter of interest.
 15. The vandal resistant data relay of claim 14wherein the extraction and emulation circuitry further includes acurrent modulator controlled by the microcontroller that transmits theactual value on a pair of conductors by emulating the predetermined setof physical and protocol properties of the two conductor hard wiredcommunication link of the irrigation controller.
 16. The vandalresistant data relay of claim 11 wherein the antenna extends from thehousing and a protective jacket surrounds the antenna.
 17. The vandalresistant data relay of claim 11 and further comprising a surfaceacoustic wave (SAW) filter coupled between the antenna and the receiver.18. The vandal resistant data relay of claim 12 wherein the mixercircuitry mixes a signal from the LO with an amplified version of theincoming RF signal to generate an intermediate frequency (IF) signal.19. The vandal resistant data relay of claim 18 and further comprising afilter that filters the IF signal.
 20. The vandal resistant data relayof claim 11 and further comprising a voltage regulator which generates apower signal for the microcontroller from an unregulated voltage on thetwo conductor hard wired communication link.